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Oxidation of atmospheric methane in soil: Measurements in the field, in soil cores and in soil samples

 

作者: Matthias Koschorreck,   Ralf Conrad,  

 

期刊: Global Biogeochemical Cycles  (WILEY Available online 1993)
卷期: Volume 7, issue 1  

页码: 109-121

 

ISSN:0886-6236

 

年代: 1993

 

DOI:10.1029/92GB02814

 

数据来源: WILEY

 

摘要:

Methane fluxes and vertical profiles of CH4mixing ratios were measured in different German soils both in situ and in soil cores. Atmospheric CH4was oxidized in the soil by microorganisms resulting in an average CH4flux of −1.39±1.5 μmol‐CH4m−2h−1. Methane deposition showed only a weak positive correlation (r2= 0.38) with soil temperature but a relatively strong negative correlation (r2= 0.61) with soil moisture indicating limitation of the CH4flux by gas transport. Diffusion experiments in soil cores showed that gas transport between atmosphere and soil was faster than microbial CH4oxidation. However, the diffusion from the gas‐filled soil pores to the CH4oxidizing microorganisms may have been limiting. The main CH4−oxidizing activity was located in a few centimeter thick subsurface soil layer at the top of the Ahhorizon, whereas no activity was found in the overlying O horizons and in deep soil below about 20‐cm depth. In contrast, the highest CO2production was found in the topmost O horizon. The effective diffusion coefficient of CH4in soil was determined using a method based on relaxation experiments with argon. The diffusion coefficient was used to model the CH4oxidation in soil cores from the vertical profiles of CH4mixing ratios. The thus calculated CH4oxidation rates and their localization in the soil profile compared fairly well with those determined directly from incubated soil samples. Fluxes were similar within a factor of 2–4 whether derived from the model, calculated from the measured CH4 oxidation rates of soil samples, or

 

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